Color filter black matrix resist composition

ABSTRACT

The present invention relates to (1) a photosensitive composition for color filter black matrix resists, containing (A) a binder resin having a carboxyl group, (B) a compound having an ethylenically unsaturated bond, (C) a photopolymerizing initiator, (D) a thiol compound having two or more mercapto-group-containing groups in which carbon atoms at the a-position and/or n-position with respect to the mercapto group have a substituent, and (E) an organic solvent, and having high sensitivity and excellent storage stability; and (2) color filterblack blackmatrix resist containing (1) the photosensitive composition for color filter black matrix resists and a black pigment (F).

CROSS-REFERENCE TO THE RELATED APPLICATIONS

This is an application filed pursuant to 35 U.S.C. Section 111 (a) withclaiming-the benefit of U.S. Provisional application Ser. No. 60/435,284filed Dec. 23, 2002, under the provision of 35 U.S.C. Section 111(b),pursuant to 35 U.S.C. Section 119(e)(1).

TECHNICAL FIELD

The present invention relates to a photosensitive composition for acolor filter black matrix resist that contains a branchedmultifunctional thiol compound and concomitantly exhibits highsensitivity and storage stability and to a color filter black matrixresist composition that uses the same.

BACKGROUND ART

Photosensitive compositions are used in printing plates, color proofs,color filters, solder resists, and photocuring inks and in various otherfields. Particularly, in recent years, room-temperature, rapid drying,solvent-free and the like properties, which are major characteristics ofphotocuring, have been attracting attention from the viewpoints ofenvironmental protection, energy saving, working safety, production costand so forth, and numerous studies and developments are under way.

Among these, in development of color filters for use in color televisionsets, liquid crystal display devices, solid image pickup devices,cameras and so forth, studies on pigment dispersed type resist for colorfilters are being made for the purpose of increasing productivity andfor achieving high resolution. A color filter have formed therein threeor more different hue patterns, such as red (R), green (G) and blue (B)with a precision of several micrometers (μm). Usually, there arearranged between such hue patterns grid-like shielding black matrices inorder to increase the contrast. In such application of the color filter,there has been an increasing demand for a photosensitive composition andthose photosensitive compositions that cure more rapidly with lowenergy, ensure formation of patterns with high resolution and havelarger curing depth and higher storage stability are sought.

A photosensitive composition is composed mainly of a photopolymerizationinitiator, a compound having an ethylenically unsaturated bond thatcures by a polymerization reaction, and various additives, and thecomponents are selected depending on the application of thephotosensitive composition.

The photopolymerization initiator is selected by its photosensitivewavelength and polymerization initiating property. The compound havingan ethylenically unsaturated bond and additives are selected by theirpolymerizability and the physical properties of the cured product. Theseare used in combination. However, some types of the compound having anethylenically unsaturated bond or of the additive, cause (1) a problemthat sufficient energy for starting photopolymerization is not obtained,(2) a problem that storage stability is not obtained, (3) a problem thatthe irradiated light cannot reach deep enough due to the thickness ofthe target cured product, resulting in insufficient curing, (4) aproblem that inhibition by oxygen occurs at a portion where thephotosensitive composition contacts the atmosphere, and so forth.

Various attempts have been made to avoid these problems; for example,irradiation of higher energy, addition of an excess amount ofphotopolymerization initiator, adoption of an oxygen shielding membrane,and so forth. However, also for saving energy and reducing productioncost, a photosensitive composition having more excellent photocuringproperties and storage stability is desired.

In particular, black matrix resist used in producing color filters aredesired to be highly sensitive and excellent in developability and alsoexcellent in storage stability. That is, color filters are usuallyproduced by forming a black matrix on a surface of a transparentsubstrate such as glass or plastic sheet and then patterns of three ormore different hues, such as red (R), green (G), blue (B) and so forthin a precision of several micrometers.

Heretofore, there have been used photosensitive compositions produced bya pigment dispersion method where a light-shielding pigment is dispersedfor black matrices. In recent years, color filters that have moreexcellent color contrast using pigments in higher concentration arebeing desired. However, use of pigments in higher concentrations lead toa decrease in sensitivity and developability, so that it has beenproposed to use a multifunctional thiol compound in order to improve thedevelopability of the photosensitive composition. However, thosephotosensitive compositions so far proposed in which multifunctionalthiol compounds are used have a disadvantage that their storagestability is poor. For example, regarding the use of a multifunctionalthiol compound in a photopolymerizable composition for color filtersthat is suitable for forming black matrices, for example, JP-A-10-253815(the term “JP-A” as used herein means an “unexamined published Japanesepatent application”), JP-A-10-253816 and JP-A-10-253817 disclosephotopolymerizing compositions that contain a multifunctional thiolcompound and an initiator selected from a group consisting of abiimidazole compound, a titanocene compound, a triazine compound and anoxazole compound, and JP-A-2000-249822 discloses a photopolymerizationinitiator including a sensitizer, an organic boron complex and acompound having a mercapto group. However, in these techniques, there isa problem that attempts to achieve high sensitivity with suchmultifunctional thiols deteriorate storage stability.

Therefore, development of a black matrix resist for color filters,having high sensitivity and excellent developability as well asexcellent storage stability and of a photosensitive composition for usetherein is desired.

An object of the present invention is to provide a photosensitivecomposition for color filter black matrix resists that has highsensitivity and excellent storage stability and a color filter blackmatrix resist composition using the photosensitive composition.

DISCLOSURE OF THE INVENTION

The inventors of the present invention have found that theabove-mentioned problems can be solved by using in a photosensitivecomposition, a multifunctional thiol compound that has a structure wherea carbon atom at α-position and/or β-position with respect to a mercaptogroup has a substituent, specifically a multifunctional thiol compoundhaving a structure which is branched on the carbon atom at α-positionand/or β-position with respect to a mercapto group, more specifically, abranched multifunctional thiol compound including two or more ofbranched structure in each of which a carbon atom at α-position and/orβ-position with respect to a mercapto group forms three or more bondswith atoms other than hydrogen atoms, thus achieving the presentinvention.

That is, the present invention relates to photosensitive compositionsfor color filter matrix resists as described in 1 to 13 below and tocolor filter black matrix resist compositions as described in 14 to 16below. 1. A photosensitive composition for color filter black matrixresists, comprising (A) a binder resin having a carboxyl group, (B) acompound having an ethylenically unsaturated bond, (C) aphotopolymerizing initiator, (D) a thiol compound having two or moremercapto-group-containing groups in which carbon atom(s) at α-positionand/or β-position with respect to the mercapto group have a substituent,and (E) an organic solvent. 2. The photosensitive composition for colorfilter black matrix resists according to 1 above, wherein at least oneof the substituents in the thiol compound (D) is an alkyl group. 3. Thephotosensitive composition for color filter black matrix resistsaccording to 2 above, wherein the alkyl group of the thiol compound (D)is a linear or branched alkyl group having 1 to 10 carbon atoms. 4. Thephotosensitive composition for color filter black matrix resistsaccording to 1 above, wherein the mercapto-group-containing group of thethiol compound (D) is represented by the following formula (1)—(CH₂)_(m)C(R¹)(R²)(CH₂)_(n)SH   (1)(in the formula, R¹ and R² independently represent each a hydrogen atomor an alkyl group, at least one of R¹ and R² is an alkyl group, m is aninteger of 0 or 1 to 2, and n is 0 or 1.) 5. The photosensitivecomposition for color filter black matrix resists according to any oneof 1 to 4 above, wherein the thiol compound (D) is an ester of amercapto group-containing carboxylic acid represented the followingformula (2)HO—CO—(CH₂)_(m)C(R¹)(R²)(CH₂)_(n)SH   (2)(in the formula, R¹ and R² independently represent each a hydrogen atomor an alkyl group, at least one of R¹ and R² is alkyl group, m is aninteger of 0 or 1 to 2, and n is 0 or 1) with a multifunctional alcohol.6. The photosensitive composition for color filter black matrix resistsaccording to 5 above, wherein the multifunctional alcohol is one or moreof compounds selected from a group consisting of alkylene glycol(provided that the alkylene group has 2 to 10 carbon atoms and may bebranched), diethylene glycol, glycerol, dipropylene glycol,trimethylolpropane, pentaerythritol and dipentaerythritol. 7. Thephotosensitive composition for color filter black matrix resistsaccording to 5 above, wherein the multifunctional alcohol is a highmolecular polymer having a hydroxyl group. 8. The photosensitivecomposition for color filter black matrix resists according to 1 above,wherein the binder resin having a carboxyl group (A) further has anethylenically unsaturated group. 9. The photosensitive composition forcolor filter black matrix resists according to 8 above, wherein thebinder resin having a carboxyl group (A) is an acrylic copolymer. 10.The photosensitive composition for color filter black matrix resistsaccording to 1 above, wherein the photopolymerization initiator (C)contains a hexaaryl biimidazole compound and/or an aminonacetophenonecompound. 11. The photosensitive composition for color filter blackmatrix resists according to 10 above, wherein the hexaaryl biimidazolecompound is represented by the following formula (3)

(in the formula, R³represents a halogen atom, R⁴ represents an alkylgroup having 1 to 4 carbon atoms that may have a substituent, or analkoxy group that may have a substituent). 12. The photosensitivecomposition for color filter black matrix resists according to 1 above,wherein the photopolymerization initiator (C) contains at least onecompound selected from the group consisting of a benzophenone-basedcompound, a thioxanthone-based compound, and a ketocoumarin-basedcompound as a sensitizer. 13. The photosensitive composition for colorfilter black matrix resists according to 1 above, wherein respectivecomponents excluding the organic solvent (E) are contained in thefollowing ratio based on the total amount of the components: (A) abinder resin having a carboxyl group 30 to 70 mass % (B) a compoundhaving an ethylenically  5 to 40 mass % unsaturated compound (C) aphotopolymerization initiator  3 to 30 mass % (D) a thiol compoundhaving two or more  3 to 30 mass % mercapto-group-containing groups inwhich carbon atoms at the α-position and/or β-position with respect tothe mercapto group have a substituent

14. A color filter black matrix resist composition comprising thephotosensitive composition for color filter black matrix resistsaccording to any one of 1 to 13 above and a black pigment (F). 15. Thecolor filter black matrix resist composition comprising thephotosensitive composition according to 14 above, wherein the blackpigment (F) contains carbon black. 16. The color filter black matrixresist composition comprising the photosensitive composition accordingto 14 above, wherein respective components excluding the organic solvent(E) are contained in the following ratios based on the total amount ofthe components: (A) a binder resin having a carboxyl group 10 to 30 mass% (B) a compound having an ethylenically  2 to 20 mass % unsaturatedcompound (C) a photopolymerization initiator  2 to 15 mass % (D) a thiolcompound having two or more  2 to 15 mass % mercapto-group-containinggroups in which carbon atoms at the α-position and/or β-position withrespect to the mercapto group have a substituent (F) a black pigment 40to 70 mass %.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described.

The photosensitive composition for color filter black matrix resists(hereinafter, referred to simply as “photosensitive composition” in somecases) comprises (A) a binder resin having a carboxyl group, (B) acompound having an ethylenically unsaturated bond, (C) aphotopolymerization initiator, (D) a thiol compound having two or moremercapto-group-containing groups in which carbon atoms at the α-positionand/or β-position with respect to the mercapto group have a substituent,and (E) an organic solvent.

Further, the color filter black matrix resist composition (hereinafter,referred to simply as “resist composition” in some cases) comprises theabove-mentioned photosensitive composition and the black pigment (F)blended therewith.

(1) (A) Binder Resin Having a Carboxyl Group

The binder resin (A) used in the present invention has a carboxyl groupin its side chain and is a component that determines various propertiesof the resist, such as film strength, heat resistance, substrateadhesion, solubility in aqueous alkali solutions (alkali developability)and so forth.

Specific examples thereof include an acrylic copolymer (AP) having acarboxyl group and an epoxy (meth)acrylate resin (EA) having a carboxylgroup. The acrylic copolymer and epoxy acrylate resin may be used incombination of two or more of them.

Among these, particularly preferred are those having a carboxyl group inthe side chain and also an ethylenically unsaturated in the side chain,and specifically, mention may be made of the above-mentioned acryliccopolymer (AP).

(i) Acrylic Copolymer (AP) Having a Carboxyl Group The acrylic copolymer(AP) having a carboxyl group is obtained by copolymerizing (a) acarboxyl-group-containing ethylenically unsaturated monomer and (b) anethylenically unsaturated monomer other than (a).

The carboxyl-group-containing ethylenically unsaturated monomer (a) isused for imparting the acrylic copolymer with alkali developability.Specific examples of the carboxyl-group-containing ethylenicallyunsaturated monomer include (meth)acrylic acid, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxyethylphthalic acid,(meth)acryloyloxyethylhexahydrophthalic acid, (meth)acrylic acid dimer,maleic acid, crotonic acid, itaconic acid, and fumaric acid.

Note that “(meth)acrylic acid” as used herein means both acrylic acidand methacrylic acid while the term “(meth)acryloyl” used herein meansboth acryloyl and methacryloyl.

The ethylenically unsaturated monomer (b) other than (a) above is usedfor controlling the strength and pigment dispersability of the film.Specific examples thereof include vinyl compounds such as styrene,α-methylstyrene, (o,m,p-)hydroxystyrenes and vinyl acetate,(meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate,n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl(meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate,cyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl(meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl(meth)acrylate, (meth)acrylonitrile, glycidyl (meth)acrylate, allylglycidyl ether, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, trifluoroethylacrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate andperfluorooctylethyl (meth)acrylate, and compounds having an amide group,such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl(meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide,N-isopropyl (meth) acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam,and N-(meth)acryloylmorpholine.

Further, there may be used those acrylic copolymers having anethylenically unsaturated bond in the side chain that are obtained byreacting a carboxyl groups in a portion of the side chain of the acryliccopolymer obtained by copolymerizing the above-mentioned monomers withan epoxy group of a compound having an epoxy group and an ethylenicallyunsaturated group in one molecule, such as glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 4-(2,3-epoxypropoxy)butyl(meth)acrylate and allyl glycidyl ether, or by reacting a part or wholeof hydroxyl groups of the acrylic copolymer with an isocyanate group ofa compound having an isocyanate group and an ethylenically unsaturatedgroup in one molecule, such as 2-methacryloyloxyethyl isocyanate.

Copolymerization ratio of (a) the carboxyl-group-containingethylenically unsaturated monomer to (b) the ethylenically unsaturatedmonomer other than the (a) is preferably 5:95 to 40:60, more preferably10:90to50:50, in mass ratio. If the copolymerization ratio of (a) isless than 5, the alkali developabililty is decreased so that it becomesdifficult to form patterns. On the other hand, if the copolymerizationratio of (a) exceeds 60, alkali development of the photocured portiontoo readily proceeds so that it becomes difficult to maintain the linewidth of the patterns at a constant value.

A preferred molecular weight of the acrylic copolymer (AP) having acarboxyl group is within the range of 1,000 to 500,000, preferably 3,000to 200,000 in a weight average molecular weight in terms of polystyreneobtained by GPC. If the molecular weight is less than 1,000, the filmstrength after curing decreases considerably. On the other hand, if themolecular weight exceeds 500,000, the alkali developability decreasesconsiderably.

(ii) Epoxy (Meth)Acrylate Compound (EA) Having a Carboxyl Group

The epoxy (meth)acrylate compound having a carboxyl group used in thepresent invention is not particularly limited, however, epoxy(meth)acrylate compound obtained by reacting a reaction product betweenan epoxy compound and an unsaturated group-containing monocarboxylicacid with acid anhydride is suitable.

The epoxy compound used in the present invention is not particularlylimited and examples thereof include epoxy compounds such as a bisphenolA type epoxy compound, a bisphenol F type epoxy compound, a bisphenol Stype epoxy compound, a phenol novolak type epoxy compound, a cresolnovolak type epoxy compound, or an aliphatic epoxy compound. These maybe used singly or in combination of two or more of them.

Examples of the unsaturated group-containing monocarboxylic acid include(meth)acrylic acid, 2-(meth)acryloyloxyethylsuccinic acid,2-(meth)acryloyloxyethylphthalic acid,(meth)acryloyloxyethylhexahydrophthalic acid, (meth)acrylic acid dimer,β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonicacid and α-cyanocinnamic acid. Further examples thereof include halfester compounds that are reaction products between a hydroxylgroup-containing acrylate and a saturated or unsaturated dibasic acidanhydride, and half ester compounds that are reaction products betweenan unsaturated group-containing monoglycidyl ether and a saturated orunsaturated dibasic acid anhydride. These unsaturated group-containingmonocarboxylic acids may be used singly or in combination of two or moreof them.

Examples of the acid anhydride include dibasic acid anhydrides such asmaleic acid anhydride, succinic acid anhydride, itaconic acid anhydride,phthalic acid anhydride, tetrahydrophthalic acid anhydride,hexahydrophthalic acid anhydride, methylhexahydrophthatlic acidanhydride, endomethylenetetrahydrophthalic acid anhydride, andmethylendomethylenetetrahydrophthalic acid anhydride, chlorendic acidanhydride and methyltetrahydrophtalic acid anhydride, aromatic polybasiccarboxylic acid anhydrides such as trimellitic acid anhydride,pyromellitic acid anhydride and benzophenonetetracarboxylic aciddianhydride, and polybasic carboxylic acid anhydride derivatives such as5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylicacid anhydride, endobicyclo-[2,2,1]-hept-5-ene-2,3-dicarboxylic acidanhydride. These may be used singly or in combination of two or more.

The molecular weight of the epoxy (meth)acrylate, compound (EA) having acarboxyl group thus obtained is not particularly limited, however, theweight average molecular weight in terms of polystyrene obtained by GPCis 1,000 to 40,000, more preferably 2,000 to 5,000.

Further, acid value (which means acid value of solid contents measuredaccording to JIS K0070, hereinafter the same will apply) of theabove-mentioned epoxy (meth) acrylate compound is 10 mgKOH/g or more,more preferably in the range of 45 mgKOH/g to 160 mgKOH/g, andparticularly preferably in the range of 50 mgKOH/g to 140 mgKOH/g inview of well balanced alkali solubility and alkali resistance of thecured film. If the acid value is smaller than 10 mgKOH/g, the alkalisolubility is deteriorated. On the contrary, if it is too large, thismay be a factor that deteriorates the characteristics such as alkaliresistance of the cured film, depending on the combinations of theconstituent components of the photosensitive composition.

(2) (B) Compound Having an Ethylenically Unsaturated Group

The compound having an ethylenically unsaturated group (B) contained inthe photosensitive composition of the present invention is other thanthe binder resin (A) described above and is used for adjusting thephotosensitivity of the photosensitive composition or adjusting thephysical properties-of cured product, such as heat resistance,flexibility and so forth. Preferably, (meth)acrylic acid esters areused.

Specific examples thereof include alkyl (meth)acrylates such as methyl(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl(meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate,tert-butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate,isooctyl (meth)acrylate, 2-ethylheyxyl (meth)acrylate, decyl(meth)acrylate; lauryl (meth)acrylate and stearyl (meth)acrylate;alicyclic (meth) acrylates such as cyclohexyl (meth) acrylate, bornyl(meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl(meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate; aromatic(meth)acrylates such as benzyl (meth)acrylate, phenyl (meth)acrylate,phenylcarbitol (meth)acrylate, nonylphenyl (meth)acrylate,nonylphenylcarbitol (meth)acrylate and nonylphenoxy (meth)acrylate;(meth)acrylates having a hydroxyl group, such as 2-hydroxyethyl(meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl(meth)acrylate, butanediol mono (meth) acrylate, glycerol (meth)acrylate, polyethylene glycol (meth)acrylate and glyceroldi(meth)acrylate; (meth)acrylates having an amino group such as2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylateand 2-tert-butylaminoethyl (meth)acrylate; (meth)acrylates having aphosphorus atom, such as methacryloxyethyl phosphate,bis(methacryloxy)ethyl phosphate and methacryolxyethyl phenyl acidphosphate; di(meth)acrylates such as ethylene glycol di(meth)acrylate,diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate,tetraethylene glycol di(meth)acrylate, polyethylene glycoldi(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycoldi(meth)acrylate, tripropylene glycol di(meth)acrylate, 1,4-butanedioldi(meth)acrylate, 1,3-butanediol di(meth)acrylate, neopentyl glycoldi(meth)acrylate, 1,6-hexanediol di(meth)acrylate and bis(glycidyl(meth)acrylate); poly(meth)acrylates such as trimethylolpropanetri(meth)acrylate, pentaerythritol tri(meth)acrylate, anddipentaerythritol hexa(meth)acrylate; modified polyol poly (meth)acrylates such as 4 mol ethylene oxide-added bisphenol Sdi(meth)acrylate, 4 mol ethylene oxide-added bisphenol Adi(meth)acrylate, fatty acid-modified pentaerythritol di(meth)acrylate,3 mol propylene oxide-added trimethylolpropane tri(meth)acrylate, and 6mol propylene oxide-added trimethylolpropane tri(meth)acrylate;polyacrylates having an isocyanuric acid skeleton, such asbis(acryloyloxyethyl) monohydroxyethyl isocyanurate,tris(acryloyloxyethyl) isocyanurate, and ε-caprolactone-added tris(acryloyloxyethyl) isocyanurate; polyester acrylates such asα,ω-diacryloyl-(bisethyleneglycol)phthalate andα,ω-tetraacryloyl-(bistrimethylolpropane)-tetrahydrophthalate; glycidyl(meth)acrylate; allyl (meth)acrylate;ω-hydroxyhexanoyloxyethyl(meth)acrylate; polycaprolactone(meth)acrylate; (meth)acryloyloxyethyl phthalate;(meth)acryloyloxyethylsuccinate; 2-hydroxy-3-phenoxypropyl acrylate;phenoxyethyl acrylate, and the like.

In addition, N-vinyl compounds such as N-vinylpyrrolidone,N-vinylformamide and N-vinylacetamide, polyester (meth)acrylate,urethane (meth)acrylate, epoxy (meth)acrylate and the like may bepreferably used as the compound having an ethylenically unsaturatedgroup.

Preferred among these are poly (meth)acrylates such astrimethylolpropane tri(meth)acrylate, pentaerythritoltetra(meth)acrylate and dipentaerythritol hexa(meth)acrylate, whichenhance high photosensitivity.

The blending ratio ((A): (B)) of (A) the binder resin to (B) thecompound having an ethylenically unsaturated group is within a range of95:5 to 50:50, preferably 90:10 to 60:40, more preferably 85:15 to 70:30in mass ratio. If the blending amount of (A) the binder resin exceeds95mass %, unpreferably the photosensitivity decreases while if theblending amount of (A) the binder resin is less than 50 mass %, the linewidth of patterns unpreferably becomes broad.

(3) (C)Photopolymerization Initiator

Components used for ordinary photopolymerization initiators (forexample, radical generators, sensitizers, etc.) may be used in thephotopolymerization initiator (C) In the present invention, thephotopolymerization initiator (C) means a composition containing aseries of compounds that initiates photopolymerization, includingordinary photopolymerization initiators, sensitizers, etc. Therefore, itmay be a single chemical substance or a combination of a plurality ofchemical substances.

Such components include, for example, biimidazole compounds and/oracetophenone compounds that act as radical generators. Further, at leastone compound selected from the group consisting of benzophenone-basedcompounds, thioxanthone-based compounds and ketocoumarin-based compoundsthat act primarily as sensitizers is included. These components may beused singly or two or more of them may be used in combination.

(i) Biimidazole-based Compound and/or Acetophenone-based Compound

As the biimidazole-based compound used in the present invention, any oneof those generally used in ordinary photopolymerization initiators canbe used. Preferable examples thereof include hexaaryl biimidazolecompounds, more preferably hexaaryl biimidazole compounds having astructure represented by the following formula (4).

In the formula (4) above, R⁵, R⁶, and R⁷ independently represent each ahalogen atom, a cyano group, or a nitro group, R⁸, R⁹, R¹⁰, R¹¹, and R¹²independently represent each a hydrogen atom, an alkyl group optionallyhaving a substituent, or an alkoxy group optionally having asubstituent. The halogen atom includes a chlorine atom, a bromine atom,a fluorine atom or the like.

Examples of the alkyl group include linear or branched ones havingpreferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.Specific examples thereof include a methyl group, an ethyl group, ann-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, at-butyl group, an n-pentyl group and an n-hexyl group. These groups mayhave a substituent such as an alkoxy group or a halogen atom.

Examples of the alkoxy group includes linear or branched ones havingpreferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.Specific examples thereof include a methoxy group, an ethoxy group, apropoxy group, an n-butoxy group, an i-butoxy group, a t-butoxy group,an n-pentyloxy group, and an n-hexyloxy group. These groups may have asubstituent such as an alkoxy group or a halogen atom.

As such a hexaaryl biimidazole compound, a compound having a structurerepresented by the following formula (3) is exemplified as particularlypreferred.

In the formula (3), R³ represents a halogen atom, R⁴ represents an alkylgroup having 1 to 4 carbon atoms optionally having a substituent or analkoxy group optionally having a substituent. Examples of the alkylgroup or alkoxy group represented by R⁴ include similar ones that areexemplified with respect to R8 to R¹² in formula (4) (provided that thenumber of carbons is 1 to 4), and particularly preferred are a methylgroup and a methoxy group. The halogen atom is particularly preferably achlorine atom.

As the acetophenone-based compound used in the present invention,hydroxyacetophenone-based compounds and aminoacetophenone-basedcompounds may be exemplified. Among these, aminoacetophenone-basedcompounds are used particularly preferably from the viewpoint ofphotosensitivity.

Examples of the hydroxyacetophenone compound includeα-hydroxyacetophenones such as 2-hydroxy-2-methyl-l-phenylpropan-1-one,2-hydroxy-2-methyl-1-phenylbutan-1-one,1-(4-methylphenyl)-2-hydroxy-2-methylpropan-1-one,1-(4-isopropylphenyl)-2-methylpropan-1-one,1-(4-butylphenyl)-2-hydroxy-2-methylpropan-1-one,2-hydroxy-2-methyl-1-(4-octylphenyl)propan-1-one,1-(4-dodecylphenyl)-2-methylpropan-1-one,1-(4-methoxyphenyl)-2-methylpropan-1-one,1-(4-methylthiophenyl)-2-methylpropan-1-one,1-(4-chlorophenyl)-2-hydroxy-2-methylpropan-1-one,1-(4-bromophenyl)-2-hydroxy-2-methylpropan-1-one,2-hydroxy-1-(4-hydroxyphenyl)-2-methylpropan-1-one,1-(4-dimethylaminophenyl)-2-hydroxy-2-methylpropan-1-one,1-(4-carboethoxyphenyl)-2-hydroxy-2-methylpropan-1-one,1-hydroxycyclohexylphenylketone, and2-hydroxy-1-(4-(2-hydroxyethoxy)-phenyl)-2-methylpropan-1-one,

Examples of the aminoacetophenone compound include α-aminoacetophenones,such as 2-dimethylamino-2 -methyl-1-phenylpropan-1-one,2-diethylamino-2-methyl-1-phenylpropan-1-one,2-methyl-2-morpholino-1-phenylpropan-1-one,2-dimethylamino-2-methyl-1-(4-methylphenyl)propan-1-one,2-dimethylamino-1-(4-ethylphenyl)-2-methylpropan-1-one,2-dimethylamino-1-(4-isopropylphenyl)-2-methylpropan-1-one,1-(4-butylphenyl)-2-dimethylamino-2-methylpropan-1-one,2-dimethylamino-1-(4-methoxyphenyl)-2-methylpropan-1-one,2-dimethylamino-2-methyl-1-[(4-methylthio)phenyl]propan-1-one,2-methyl-1-[(4-methylthio)phenyl]-2-morpholino-propan-1-one,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and2-benzyl-2-dimethylamino-1-(4-dimethylaminophenyl)-butan-1-one.

(ii) Sensitizer

In the present invention, typical sensitizers employed in ordinaryphotopolymerization initiators may be used. To enhance the sensitivity,it is preferable that at least one compound selected from the groupconsisting of benzophenone-based compounds, thioxanthone-based compoundsand ketocoumarin-based compounds is used.

Specifically, use may be made of benzophenone-based compounds such asbenzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone,4-benzoyl-4′-methyldiphenyl sulfide,4,4′-bis(dimethylamino)benzophenone, and4,4′-bis(diethylamino)benzophenone, thioxanthone-based compounds such asthioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone,2,4-diethylthioxanthone, isopropylthioxanthone,2,4-diisopropylthioxanthone and 2-chlorothioxanthone, ketocoumarin-basedcompounds such as 3-acethylcoumarin, 3-acetyl-7-diethylaminocoumarin,3-benzoylcoumarin, 3-benzoyl-7-diethylaminocoumarin,3-benzoyl-7-methoxycoumarin, 3,3′-carbonylbiscoumarin,3,3′-carbonylbis(7-methoxycoumarin), and3,3′-carbonylbis(5,7-dimethoxycoumarin). These may be used singly ormixture of two or more of them may be used.

The blending ratio of the above-mentioned sensitizer in thephotopolymerization initiator is not particularly limited, however,preferably it is 5 to 40 mass %, more preferably 10 to 30 mass % of thetotal amount of the photopolymerization initiator. If the blending ratioof these sensitizers is too little, the sensitivity decreases while ifthe blending ratio of these sensitizers is too much, light transmissiontoward the bottom of the resist is inhibited, so that the form of thecross-section of the resist becomes an inverted trapezium, resulting ina decreased precision of resolution, which is not preferable.

Other components of the photopolymerization initiator used in thepresent invention include benzoin methyl ether, benzoin ethyl ether,benzoin isopropyl ether, benzyl dimethyl ketal, α-halogenoacetophenones,methylphenyl glyoxylate, benzil, anthraquinone, phenanthrenequinone,camphor quinone isophthalophenone, acylphosphine oxide, α-acyloximeester, camphor quinone and other compounds. In addition,organoborate-based compounds described in JP-A-2000-249822 may be used.

(4) (D) Thiol Compound Having two or more Mercapto-Group-ContainingGroups in which Carbon Atoms at α-Position and/or β-Position withRespect to the Mercapto Group have a Substituent

The thiol compound (D) used in the present invention have two or moremercapto-group-containing groups in which carbon atoms at α-positionand/or β-position with respect to the mercapto group have a substituent.Here, it is preferable that at least one of the above-mentionedsubstituents be an alkyl group.

That is, preferably, the thiol compound (D) is a branched thiol compoundthat includes a structure of branching on carbon atom(s) at theα-position and/or β-position with respect to the mercapto group, or abranched thiol compounds having a so-called branched structure, in whichcarbon atoms at α-position and/or β-position with respect to themercapto group have three or more bonds with atoms other than hydrogenatoms. For example, the thiol compound (D) is, for example, is a thiolcompound in which at least one of substituents that is at α-positionand/or β-position with respect to the mercapto group in chains otherthan the main chain is an alkyl group. Here, the main chain representsthe longest chain that contains the mercapto group and is constituted byatoms other than hydrogen atoms.

Among them, the thiol compounds in which the above-mentioned mercaptogroup-containing-group is represented by the following formula (1) arepreferable.—(CH₂)_(m)C(R¹)(R²)(CH₂)_(n)SH   (1)

In the formula (1), R¹ and R² independently represent each a hydrogenatom or an alkyl group, at least one of R¹ and R² is an alkyl group. Inother words, R¹ and R² do not represent hydrogen atoms simultaneously.When R¹ and R² are both alkyl groups, they may be the same or different.m is an integer of 0 or 1 to 2, and n is 0 or 1.

The above-mentioned alkyl group (in the formula (1) above, R¹ or R²) ispreferably a linear or branched alkyl group. Specific examples thereofinclude a methyl group, an ethyl group, an n-propyl group, and aniso-propyl group, more preferably a methyl group or an ethyl group.

Note that the thiol compound (D) of the present invention is amultifunctional compound having two or more mercapto-group-containinggroups described above. Being multifunctional, the thiol compound (D) ofthe present invention can provide higher sensitivity than monofunctionalcompounds can.

Further, the mercapto-group-containing group represented by the formula(1) above preferably assumes a carboxylic acid derivative structure asrepresented by the following formula. Here, R¹, R², m and n are the sameas defined in the formula (1) above.—O—CO—(CH₂)_(m)C(R¹)(R²)(CH₂)_(n)SH

The above-mentioned thiol compound (D) is more preferably an ester of amercapto group-containing carboxylic acid represented by the formula (2)below and an alcohol.HO—CO—(CH₂)_(m)C(R¹)(R²)(CH₂)_(n)SH   (2)

Here, in the formula (2) above, R¹ and R² independently represent each ahydrogen atom or an alkyl group, at least one of R¹ and R² is an alkylgroup. m is an integer of 0 or 1 to 2, and n is 0 or 1. Specificexamples of the alkyl group include those described with respect to theformula (1) described above.

Since the thiol compound (D) of the present invention is amultifunctional thiol compound, a multifunctional alcohol is moredesirable as the alcohol that is subjected to esterification reactionwith the compound of the formula (2). Examples of the multifunctionalalcohol include an alkylene glycol (here, the number of carbons of thealkylene group is preferably 2 to 10, and the carbon chain may bebranched), diethyleneglycol, glycerin, dipropylene glycol,trimethylolpropane, pentaerythritol, dipentaerythritol, and highmolecular polymer having a hydroxyl group.

The high molecular polymer having a hydroxyl group preferably includesan acrylic copolymer having a hydroxyl group. The weight averagemolecular weight of the high molecular polymer having a hydroxyl groupin terms of polystyrene as measured by GPC is not particularly limited,however, preferably 1,000 to 50,000.

Examples of the mercapto-group-containing carboxylic acid of the formula(2) above include 2-mercaptopropionic acid, 3-mercaptobutyric acid,2-mercaptobutyric acid, 2-mercaptoisobutyric acid, 4-mercaptovalericacid, and 3-mercaptovaleric acid.

Specific examples of the thiol compound having the structure of theformula (1) above according to the present invention include thefollowing compounds.

Examples of hydrocarbon dithiols include 2,5-hexanedithiol,2,9-decandithiol and 1,4-bis(1-mercaptoethyl)benzene.

Examples of compound having an ester bond in structure include phthalicacid di(1-mercaptoethyl ester), phthalic acid di(2-mercaptopropylester), phthalic acid di(3-mercaptobutyl ester) and phthalic aciddi(3-mercaptoisobutyl ester).

Preferred examples thereof include ethylene glycolbis(2-mercaptopropionate), diethylene glycol bis(2-mercaptopropionate),1,2-propylene glycol. bis(2-mercaptopropionate), 1,2-butanediolbis(2-mercaptopropionate), 1,3-butanediol bis(2-mercaptopropionate),1,4-butanediol bis(2-mercaptopropionate), 1,8-octanediolbis(2-mercaptopropionate), trimethylolpropanetris(2-mercaptopropionate), pentaerythritoltetrakis(2-mercaptopropionate), dipentaerythritolhexakis(2-mercaptopropionate), ethylene glycol bis(3-mercaptobutyrate),diethylene glycol bis(3-mercaptobutyrate), 1,2-propylene glycolbis(3-mercaptobutyrate), 1,2-butanediol bis(3-mercaptobutyrate),1,3-butanediol bis(3-mercaptobutyrate), 1,4-butnediolbis(3-mercaptobutyrate), 1,8-octanediol bis(3-mercaptobutyrate),trimethylolpropane tris(3-mercaptobutyrate), pentaerythritoltetrakis(3-mercaptobutyrate), dipentaerythritolhexakis(3-mercaptobutyrate), ethylene glycol bis(2-mercaptoisobutyrate),diethylene glycol bis(2-mercaptoisobutyrate), 1,2-propylene glycolbis(2-mercaptoisobutyrate), 1,2-butanediol bis(2-mercaptoisobutyrate),1,3-butanediol bis(2-mercaptoisobutyrate), 1,4-butnediolbis(2-mercaptoisobutyrate), 1,8-octanediol bis(2-mercaptoisobutyrate),trimethylolpropane tris(2-mercaptoisobutyrate), pentaerythritol tetrakis(2-mercaptoisobutyrate), dipentaerythritolhexakis(2-mercaptoisobutyrate), ethylene glycol bis(4-mercaptovalerate),diethylene glycol bis(4-mercaptovalerate), 1,2-propylene glycolbis(4-mercaptovalerate), 1,2-butanediol bis(4-mercaptovalerate),1,3-butanediol bis(4-mercaptovalerate), 1,4-butnediolbis(4-mercaptovalerate), 1,8-octanediol bis(4-mercaptovalerate),trimethylolpropane tris(4-mercaptovalerate), pentaerythritoltetrakis(4-mercaptovalerate), and dipentaerythritolhexakis(4-mercaptovalerate).

The thiol compound (D) preferably includes a thiol compound (a)represented by the following formula (a).(L-CO—O—CH₂—)₃—C—CH₂—CH₃   (a)

In the formula (a), L is a mercapto-group-containing group representedby the above-mentioned formula (1). That is, the thiol compound (a) hasthree mercapto-group-containing groups obtained by usingtrimethylolpropane as the starting material multifunctional alcohol.Note that more preferable examples of thiol compound (a) include thosein which the mercapto group is secondary (a-1) and those in which themercapto group is tertiary (a-2).

(a-1): Thiol compound Obtained by using Trimethylolpropane as a StartingMaterial Multifunctional Alcohol and Whose Mercapto Group is Secondary

This thiol compound is a thiol compound represented by the generalformula (a) above, wherein either one of R¹ and R² in L (whichcorresponds to the mercapto-group-containing group represented by theformula (1) above) is a hydrogen atom. A preferable specific example ofsuch a thiol compound (a-1) is trimethylolpropanetris(3-mercaptobutyrate) (TPMB).

(a-2): Thiol Compound Obtained by using Trimethylolpropane as a StartingMaterial Multifunctional Alcohol and Whose Mercapto Group is Tertiary

This thiol-compound is a thiol compound represented by the generalformula (a) above, wherein both R¹ and R² in L (which corresponds to themercapto-group-containing group represented by the formula (1) above)are alkyl groups. A preferable specific example of such a thiol compound(a-2) is trimethylolpropane tris(2-mercaptoisobutyrate) (TPMIB).

The production method for the thiol compound (D) is not particularlylimited. Ester of the mercapto group-containing carboxylic acid and analcohol can be obtained by reacting the mercapto group-containingcarboxylic acid represented by the formula (2) described above with analcohol by a conventional method. The conditions of the esterificationreaction are not particularly limited and may be selected appropriatelyfrom the conventionally known reaction conditions

By use of a branched multifunctional thiol compound as specified above,a photosensitive composition having high sensitivity and excellentstorage stability can be obtained in the present invention. The thiolcompounds may be used singly or two or more of them may be used incombination.

(5) (E) Organic Solvent

The organic solvent used in the present invention is not particularlylimited so far as it dissolves or disperses the above-mentionedrespective components that constitute the photosensitive composition forcolor filter black matrix resists of the present invention. Specificexamples thereof include methanol, ethanol, isopropanol, toluene,xylene, ethylbenzene, cyclohexane, isophorone, cellosolve acetate,diethylene glycol dimethyl ether, ethylene glycol diethyl ether, methylcellosolve, ethyl cellosolve, butyl cellosolve, propylene glycolmonomethyl ether, propylene glycol monomethyl ether acetate, propyleneglycol monoethyl ether acetate, diethylene glycol ethyl ether acetate,methyl methoxypropionate, ethyl methoxypropionate, methylethoxypropionate, ethyl ethoxypropionate, ethyl acetate, isoamylacetate, ethyl lactate, acetone, methyl ethyl ketone, cyclohexanone,N,N-dimethylformamide, and N-methylpyrrolidone. These may be used singlyor two or more of them may be used in combination.

The photosensitive composition for color filter black matrix resists ofthe present invention is desirably conditioned such that theconcentration of solid content is 5 to 30 mass %, preferably 10 to 25mass % by use of these organic solvents.

(6) (F) Black Pigment

As for the black pigment (F) used in the color filter black matrixresist composition of the present invention, carbon black, acetyleneblack, lamp black, graphite, iron black, aniline black, cyanine black,titanium black are exemplified, or red, green and blue organic pigmentscan be mixed and used as black pigment. Among them, carbon black isparticularly preferable from the viewpoint of light shielding ratio andimage characteristics.

Examples of the carbon black include the following ones. Manufactured byMitsubishi Chemical Corporation: MA7, MA8, MA11, MA100, MA220, MA230,#52, #50, #47, #45, #2700, #2650, #2200, #1000, #990, #900. Manufacturedby Degussa: Printex 95, Printex 90, Printex 85, Printex 75, Printex 55,Printex 45, Printex 40, Printex 30, Printex3, Printex A, Printex G,Special Black 4, Special Black 550, Special Black 350, Special Black250, Special Black 100. Manufactured by Cabot Corporation: Monarch 460,Monarch 430, Monarch 280, Monarch 120, Monarch 800, Monarch 4630, REGAL99, REGAL 99R, REGAL 415, REGAL 415R, REGAL 250, REGAL250R, REGAL 330,BLACK PEARL S480, PEARL S130. Manufactured by Columbian Carbon Co.:Raven 11, Raven 15, Raven 30, Raven 35, Raven 40, Raven 410, Raven 420,Raven 450, Raven 500, Raven 780, Raven 850, Raven 890H, Raven 1000,Raven 1020, Raven 1040, Raven 1060, Raven 1080, Raven 1255.

The above-mentioned carbon blacks may be used in combination with otherblack inorganic or organic pigments.

(7) Other Optional Components

The color filter black matrix resist composition of the presentinvention may contain, in addition to these essential components, apigment dispersant, an adhesion improver, a leveling agent, adevelopment improver, an antioxidant, a heat polymerization inhibitorand so forth. In particular, in the case of the color filter blackmatrix resist composition of the present invention, it is important thatthe coloring material is finely dispersed and the dispersion state isstabilized for obtaining stable quality and therefore, it is in somecases desirable that a pigment dispersant is blended.

The pigment dispersant has affinity for both pigment and binder resin,and examples thereof include surfactants such as nonion, cation andanion, and polymer dispersants. Among these, polymer dispersants arepreferable. In particular, polymer dispersants having functional groupssuch as primary, secondary or tertiary amino groups, basic functionalgroups such as pyridine, pyrimidine, pyrazine and the likenitrogen-containing heterocyclic rings or amide groups, and urethanegroups are advantageously used.

Specific examples of the heat polymerization inhibitor that is added forthe purpose of preventing polymerization during storage includep-methoxyphenol, hydroquinone, catechol, tert-butylcatechol,phenothiazine, and methoquinone.

Further, depending on the purpose, a fluorescent brightener, asurfactant, a plasticizer, a flame retardant, an ultraviolet absorbent,a foaming agents a fungicide, antistatic agent, a magnetic substance, anelectro conducting material, an antifungal or antibacterial material, aporous adsorbent, a fragrant material and the like may be added.

(8) Blending Ratios

The blending ratios of the respective constituent components in thephotosensitive composition for color filter black matrix resists of thepresent invention are not particularly limited; however, ratios of thecomponents are preferably set to the following ratios based on the totalamount (total solid content) of the components excluding

(E) The Organic Solvent.

The blending ratio of (A) binder resin having a carboxyl group is within30 to 70 mass %, preferably 35 to 65 mass %. If the amount of the binderresin is too small, there are defects that adhesion to the substrate isdeteriorated or the alkali developability of the photocured portion isdecreased. On the other hand, if the amount of the binder resin is toolarge, there is a defect that light shielding property is deteriorated.

The blending ratio of (B) the compound having an ethylenicallyunsaturated group is within 5 to 40 mass %, preferably 10 to 30 mass %.If the amount of the compound having an ethylenically unsaturated groupis too small, there is a defect that the photosensitivity is decreasedwhile if the amount of that compound is too large, there is a defectthat resist patterns tend to become broader than the line width of thephotomask.

The blending ratio of (C) the photopolymerization initiator is within 3to 30 mass %, preferably 5 to 20 mass %. If the amount of thephotopolymerization initiator is too small, there is a defect that thephotosensitivity is decreased while if the amount of thephotopolymerization initiator is too large, there is a defect thatresist patterns tend to become broader than the line width of thephotomask.

The blending ratio of (D) the thiol compound having two or moremercapto-group-containing groups in which carbon atoms at α-positionand/or β-position have a substituent is within 3 to 30 mass %,preferably 5 to 20 mass %. If the ratio of the thiol compound is toosmall, there is a defect that the photosensitivity is decreased while ifthe ratio of the thiol compound is too large, there is a defect thatresist patterns tend to become broader than the line width of thephotomask.

Further, in the resist composition of the present invention, in the casewhere the photosensitive composition contains a black pigment (F) inaddition to the above-mentioned components, the blending ratios of therespective constituent components with respect to the total amount(total solid content) of the components excluding the organic solvent(E) are preferably set as follows.

The blending ratio of (A) the binder resin having a carboxyl group iswithin 10 to 30 mass %, preferably 15 to 25 mass %. If the amount of thebinder resin is too small, there is a defect that the adhesion to thesubstrate is deteriorated. On the other hand, if the amount of thebinder resin is too large, there is a defect that the light shieldingproperty is deteriorated.

The blending ratio of (B) the compound having an ethylenicallyunsaturated group is within 2 to 20 mass %, preferably 3 to 15 mass %.If the amount of the compound having an ethylenically unsaturated groupis too small, there is a defect that the photosensitivity is decreasedwhile if the amount of that compound is too large, there is a defectthat resist patterns tend to become broader than the line width of thephotomask.

The blending ratio of (C) the photopolymerization initiator is within 2to 15 mass %, preferably 5 to 10 mass %. If the amount of thephotopolymerization initiator is too small, there is a defect that thephotosensitivity is decreased while if the amount of thephotopolymerization initiator is too large, there is a defect thatresist patterns become broader than the line width of the photomask.

The blending ratio of (D) the thiol compound having two or moremercapto-group-containing groups in which carbon atoms at α-positionand/or β-position have a substituent is within 2 to 15 mass %,preferably 5 to 10 mass %. If the ratio of the thiol compound is toosmall, there is a defect that the photosensitivity is decreased while ifthe ratio of the thiol compound is too large, there is a defect thatresist patterns become broader than the line width of the photomask.

The blending ratio of (F) the black pigment is within 40 to 70 mass %,preferably 45 to 65 mass %. If the ratio of the amount of the blackpigment is too small, there is a defect that the light shieldingproperty is deteriorated while if the amount of the black pigment (F) istoo large, there is a defect that the photosensitivity is decreased oradhesion to the substrate is deteriorated.

(9) Production Method

The photosensitive composition of the present invention can be producedby mixing or premixing (A) a binder resin having a carboxyl group, (E)an organic solvent, (F) a black pigment, and optionally a pigmentdispersant, performing dispersing treatment, and further mixing anddissolving (B) a compound having an ethylenically unsaturated group, (C)a photopolymerization initiator, and (D) a thiol compound having two ormore mercapto-group-containing groups in which carbon atoms atα-position and/or β-position have a substituent.

The dispersing machines for performing dispersing treatment include rollmills such as a two-roll mill and a three-roll mill, ball mills such asa ball mill and a vibrating ball mill, a paint conditioner and beadmills such as a continuous disk type bead mill and a continuous annulartype bead mill. A continuous annular type bead mill is particularlypreferable in that pulverization and dispersion is achieved in a shortperiod of time, that particle size distribution after the dispersion issharp, and that it is easy to control the temperature duringpulverization and dispersion so that properties of the dispersion can beprevented from changing.

The continuous annular type bead mill is of a structure having a vessel(cylindrical body) provided with an inlet and an outlet for a materialand a rotor (rotating body) formed with grooves for stirring beads,inserted into the vessel. In a gap portion between the double cylinderswhich the vessel and the rotor constitute, beads are imparted movementby the rotation of the rotor to effect pulverization, shearing andgrinding, so that the black pigment can be efficiently pulverized anddispersed. The sample is introduced through the inlet on one end of thevessel and converted into fine particles and discharged through theoutlet on the side opposite to the inlet part and this procedure isrepeated until a necessary particle size distribution can be obtained.The time in which the sample is substantially subjected to pulverizingand dispersing treatment within the vessel is called retention time.

Examples of such continuous annular type mead mill include Spike Mill(trade name) manufactured by Inoue Seisakusho Co., Ltd. and OB-Mill(trade name) manufactured by Turbo Kogyo Co., Ltd.

Preferable dispersion conditions for the continuous annular type beadmill are as follows. The size (diameter) of beads to be used ispreferably 0.2 to 1.5 mm, more preferably 0.4 to 1.0 mm. If the size ofthe beads is less than 0.2 mm, the weight of a single bead becomes toosmall so that the pulverization energy a single bead has becomes low sothat pulverization of the pigment is difficult to proceed. If the sizeof the beads exceeds 1.5 mm, collision frequency between the beads isreduced so that it becomes difficult to perform pulverization of carbonblack in a short period of time. The material of bead is preferably aceramic such as zirconia or alumina, or stainless steel, having specificgravity of 4 or more, to enhance the pulverization efficiency.

The peripheral speed of the rotor is preferably 5 to 20 m/second, morepreferably 8 to 15 m/second. If the peripheral speed is less than 5m/second, the pulverization or dispersion of the pigment cannot beperformed efficiently. If the peripheral speed of the rotor exceeds 20m/second, the temperature of the pigment dispersion becomes too high dueto friction heat, to unpreferably cause denaturation in properties suchas increase in viscosity. The temperature during dispersing ispreferably within the range of 10 to 60° C., more preferably roomtemperature to 50° C. The temperature of less than 10° C. is notpreferable since the moisture in the atmosphere is mixed in thedispersion due to dew formation. On the other hand, the temperatureexceeding 60° C. unpreferably causes denaturation in properties such asincrease in viscosity.

The retention time is preferably 1 to 30 minutes, more preferably 3 to20 minutes. If the retention time is shorter than 1 minute, pulverizingand dispersing treatment be comes insufficient while if the retentiontime exceeds 30 minutes, denaturation of the dispersion occurs,resulting in an increase in viscosity.

(10) Production Method for a Color Filter

The production method for color filters using the color filter blackmatrix resist composition of the present invention will be describedtaking an example of a color filter for a liquid crystal display whichis formed by laminating a black matrix resist composition, pixels, and aprotective film in this order.

The color filter black matrix resist composition of the presentinvention is coated onto a transparent substrate. Then, after thesolvent is dried in an oven or the like, the resultant is exposedthrough a photomask and developed to form a black matrix pattern,followed by post-baking to complete a black matrix.

Here, the transparent substrate is not particularly limited andinorganic glasses such as silica glass, borosilicate glass, and limesoda glass coated with silica on its surface, films or sheets ofpolyesters such as polyethylene terephthalate, polyolefins such aspolypropylene and polyethylene, thermoplastic plastics such aspolycarbonate, polymethyl methacrylate, and polysulfones, thermosettingresins such as epoxy resins and polyester resins are preferably used.Such transparent substrates may have been subjected to corona dischargetreatment, ozone treatment, thin film forming treatment of variouspolymers such as silane coupling agent, urethane polymer, and so forth.

In addition to dip coating, roll coater, a wire bar, a flow coater, adie coater, and a spray coating, a rotation coating method such asspinner is used advantageously.

The solvent is dried in a drying apparatus such as a hot plate, an IRoven, or a convection oven. Preferable drying conditions are 40 to 150°C. for a drying time in the range of 10 seconds to 60 minutes. Also, thesolvent may be dried in a vacuum state.

The exposure method is as follows. After a gap of 50 to 200 μm isprovided above the sample, a photomask is placed thereon and image-wiseexposure through the photomask is performed. Examples of the lightsource used for the exposure include lamp light sources such as a xenonlamp, a high pressure mercury lamp, a super high pressure mercury lamp,a metal halide lamp, a medium pressure mercury lamp, and a low pressuremercury lamp, and laser light sources such as an argon ion laser, a YAGlaser, an excimer laser, and a nitrogen laser. When only light with aspecified wavelength of the irradiated light is used, an optical filtermay be used.

The development treatment is performed by developing a resist (whichrefers to a color filter black matrix resist composition or curedproduct thereof, hereinafter the same is true) using a developingsolution by a dip, shower, or paddle method or the like. The developingsolution is not particularly limited so far as it is a solvent that candissolve unexposed portion of a resist film. For example, acetone,methylene chloride, trichlene, cyclohexanone and the like organicsolvents may be used. However, many of organic solvents causeenvironmental pollution, have toxicity to human body, and have a risk ofcausing fire, so that it is preferable to use alkali developers freefrom such risks. Examples of such alkali developer include aqueoussolutions containing inorganic alkali agents such as sodium carbonate,potassium carbonate, sodium silicate, potassium silicate, sodiumhydroxide, and potassium hydroxide, or organic alkali agents such asdiethanolamine, triethanolamine and tetaralkylammonium hydroxide. Thealkali developer may contain a surfactant, a water-soluble organicsolvent, a low molecular compound having a hydroxyl group or a carboxylgroup, as necessary. In particular, surfactants, many of which haveeffects of improving developability, resolution, and stain, can bepreferably added to the alkali developer.

Examples of surfactant for developing solution include anionicsurfactants having a sodium naphthalenesulfonate group or a sodiumbenzenesulfonate group, nonionic surfactants having a polyalkyleneoxygroup, and cationic surfactants having a tetraalkylammonium group.

The developing process is not particularly limited, however, developingis performed usually at a temperature of 10 to 50° C., preferably 15 to45° C. by a dipping development method, a spray development method, abrush development method, a supersonic development method or the like.

The post baking is performed using the same apparatus as used for thesolvent drying in a temperature range of 150 to 300° C. for 1 to 120minutes. The post baking is performed in order to make the curingreaction of the resist composition more complete by heat.

The black matrix thus obtained may advantageously have a film thicknessin the range of 0.1 to 1.5 μm, preferably 0.2 to 1.2 μm and further itis preferable that the optical density of the black matrix at such filmthickness be 3 or more in order to function as a black matrix.

The black matrix pattern prepared in this step has an opening on theorder of 20 to 200 μm between black matrices. In a later step, pixelsare formed in this opening space.

Then, a plurality of color pixels are formed in the opening of the blackmatrix. Usually, the colors of the pixels are three colors, i.e., red(R), green (G), and blue (B). The photosensitive composition is coloredwith a pigment or dye. First, the photosensitive composition is coatedonto the transparent substrate on which the black matrix pattern ismounted. Then, a solvent is dried in an oven or the like so that acolored layer of a first color is formed on the entire surface of theblackmatrix. Usually, a color filter includes pixels of a plurality ofcolors; unnecessary portions are removed by a photolithographic methodto form a pixel pattern in the desired first color. The thickness of thepixel is on the order of 0.5 to 3 μm. This procedure is repeated by thenumber of times equal to the number of required colors to form pixelshaving a plurality of colors and thus a color filter is produced.Although it is preferable that the apparatus and chemicals used in thestep for forming each pixel are the same as those used for forming theblack matrix, there is no problem if they are different.

Thereafter, a protective layer is laminated as necessary. The protectivelayer may be made of acrylic resins, epoxy resins, silicone resins,polyimide resins or the like and is not particularly limited.

Further, other than the above method, there is a so-called backsideexposure method, that is, a method in which after patterned pixels arepreliminarily formed on a transparent substrate, the opposite side(backside) of the transparent substrate is coated with a black matrixresist composition, and then the transparent substrate is exposed tolight from the front side to form a black matrix between the pixelsusing the pixels as masks.

Finally, lamination and patterning of an ITO (indium-tin oxide)transparent electrode is performed by a general method as necessary.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described by means ofExamples. However, the present invention is not limited to the Examples.In the Examples, “part” means mass part and “%” means mass %. Note thatthe prepared photosensitive composition is called “resist” for the sakeof simplicity.

SYNTHESIS EXAMPLE 1 Synthesis of Acrylic Copolymer (AP-1) Having aCarboxyl Group

In a four-necked flask equipped with a dropping funnel, a thermometer, acondenser tube and a stirrer, 37.5 mass parts of methacrylic acid (MA),19.0 mass parts of methyl methacrylate (MMA), 18.5 mass parts of n-butylmethacrylate (BMA), 0.75 mass part of 2-mercaptoethanol, and 225.0 massparts of propylene glycol methyl ether (PGM) were charged, and theinside of the four-necked flask was purged with nitrogen for one hour.Further, the temperature was elevated to 90° C. in an oil bath, and thena mixture of 37.5 mass parts of MA, 19.0 mass parts of MMA, 18.5 massparts of BMA, 0.75 mass part of 2-mercaptoethanol, 225.0 mass parts ofPGM, and 3.2 mass parts of 2,2′-azobisisobutyronitrile (AIBN) wasdripped over 1 hour. After polymerization was performed for 3 hours, themixture was heated to 100° C. and a mixture of 1.0 mass part of AIBN and15.0 mass parts of propylene glycol methyl ether acetate (PMA) wasadded, and then polymerization was performed for additional 1.5 hours,followed by standing to cool. Thereafter, the inside of the four-neckedflask was air-purged, and 61.5 mass parts of glycidyl methacrylate(GMA), 3.6 mass parts of tetra-n-butylammonium bromide (TBAB), and 0.15mass part of methoquinone were added. The reaction was performed at 80°C. for 8 hours to add GMA to the carboxyl group of the acryliccopolymer. The obtained GMA-added acrylic copolymer was named AP-1. AP-1had a solid content concentration of 30.5%, a solid content acid valueof 116 mgKOH/g, and a weight average molecular weight of 14,000 in termsof polystyrene as measured by GPC.

SYNTHESIS EXAMPLE 2 Synthesis of Acrylic Copolymer (AP-2) Having aCarboxyl Group

In a four-necked flask equipped with a dropping funnel, a thermometer, acondenser tube and a stirrer, 17.5 mass parts of MA, 30.0 mass parts ofMMA, 7.5 mass parts of benzyl methacrylate (BzMA), 20.0 mass parts of2-hydroxyethyl methacrylate (HEMA), 0.75 mass part of 2-mercaptoethanol,and 225.0 mass parts of PMA were charged and the inside of thefour-necked flask was nitrogen-purged. Further, the temperature waselevated to 90° C. in an oil bath, and then a mixture of 17.5 mass partsof MA, 30.0 mass parts of MMA, 7.5 mass parts of BzMA, 20.0 mass partsof HEMA, 75 mass part of 2-mercaptoethanol, 225.0 mass parts of PMA, and3.2 mass parts of AIBN was dripped over 1 hour. After polymerization wasperformed for 3 hours, the mixture was heated to 100° C. and a mixtureof 1.0 mass part of AIBN and 15.0 mass parts of PMA was added, and thenpolymerization was performed for additional 1.5 hours, followed bydecreasing the temperature to 60° C. Thereafter, the inside of thefour-necked flask was air-purged, and 48.0 mass parts of2-methacryloyloxyethyl isocyanate (MEI) manufactured by SHOWA DENKOK.K., 0.15 mass part of dibutyltin dilaurate and 0.15 mass part ofmethoquinone were added and reaction was performed at 60° C. for 5 hoursto add MEI to the hydroxyl group of the acrylic copolymer. The obtainedMEI-added acrylic copolymer was named AP-2. AP-2 had a solid contentconcentration of 29.5%, a solid content acid value of 114mgKOH/g, and aweight average molecular weight of 13,000 in terms of polystyrene asmeasured by GPC.

SYNTHESIS EXAMPLE 3 Synthesis of Dispersant (DP-1)

In a four-necked flask equipped with a reflux condenser, a thermometer,a stirrer, and a dropping funnel, 40 mass parts of cyclohexanone wascharged and the liquid temperature was maintained at 100° C. Undernitrogen atmosphere, a mixed solution consisting of 12 mass parts of NKEster M-20G (methoxydiethylene glycol methacrylate) manufactured byShin-Nakamura Chemical Co., Ltd., 4 mass parts of Macromonomer AA-6(methyl methacrylate macromonomer) manufactured by Toa Gosei Co., Ltd.,8 mass parts of Light Ester DQ-100 (dimethylaminoethyl methacrylate,quaternarized product) manufactured by Kyoeisha Chemical Co., Ltd., 16mass parts of Light Ester DM (dimethylaminoethyl methacrylate)manufactured by Kyoeisha Chemical Co., Ltd., 0.4 mass part ofn-dodecylmercaptan, 0.8 mass part of AIBN and 20 mass parts ofcyclohexanone was dripped over about 3 hours. After completion of thedropping, further 0.5 mass part of AIBN was added and reaction wasperformed at 100° C. for 2 hours. The weight average molecular weight ofthe obtained copolymer measured in terms of polystyrene by GPC was20,000. The solid content concentration was 40.0%. This dispersant wasnamed DP-1.

SYNTHESIS EXAMPLE 4 Synthesis of Photopolymerization Initiator Component“2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-methylphenyl)-1,2′-biimidazole(MHABI)”

In a 1-L volume egg-plant shaped flask, 27.50 g (115 mmol) of4,4′-dimethylbenzil, 16.25 g (116 mmol) of o-chlorobenzaldehyde, 69.45 g(901 mmol) of ammonium acetate, and 450 g of acetic acid were introducedand reaction was performed at 117° C. for 5 hours while stirring. Afterstanding to cool, the reaction mixture was slowly charged in 2 L ofdeionized water being stirred and2-chlorophenyl-4,5-bis(4-methylphenyl)imidazole was precipitated.Thereafter, 2-chlorophenyl-4,5-bis(4-methylphenyl)imidazole was filteredand washed with water and then dissolved in 500 g of methylene chloride.The solution was charged in a 2 L volume four-necked flask and cooled to5 to 10° C. To this was added a mixed solution consisting of 117.6 g(357 mmol) of potassium ferricyanide, 44.7 g of sodium hydroxide, and600 g of deionized water over 1 hour while stirring. Further, reactionwas performed at room temperature for 18 hours. The reaction mixture waswashed with deionized water 3 times and then dehydrated over about 50 gof anhydrous magnesium sulfate, followed by evaporation of methylenechloride under reduced pressure. As a result, crystals of MHABI wereformed. MHABI was recrystallized from ethanol, filtered, and dried. As aresult, 36.5 g (yield 88.7%) of pale yellow crystals were obtained.

SYNTHESIS EXAMPLE 5 Synthesis of Photopolymerization Initiator Component“1,2-propylene glycol bis(3-mercaptobutyrate) (PGMB)”.

In a 100 mL volume egg-plant shaped flask, 3.04 g (40 mmol) of1,2-propylene glycol, 10.57 g (88.mmol) of 3-mercaptobutanoic acid, 0.61g (3.2 mmol) of p-toluenesulfonic acid monohydrate, and40g of toluenewere charged and a Dean-Stark apparatus and a condenser tube wereattached to the flask. The content of the flask was heated at an oilbath temperature of 140° C. while stirring. After 2 hours from the startof the reaction, 0.61 g (3.2 mmol) of p-toluenesulfonic acid monohydratewas added and then 0.30 g (1.6 mmol) of p-sulfonic acid monohydrate wasadded after 4 hours from the start of the reaction. Further, thereaction was continued for another 1 hour and the reaction mixture wasleft to cool, followed by neutralizing the reaction mixture with 100 mlof an aqueous 10% sodium hydrogen carbonate solution. Further, thereaction mixture was washed with deionized water 3 times and dehydratedand dried over anhydrous magnesium sulfate. Then, toluene was evaporatedand the residue was subjected to silica gel column chromatography topurify PGMB. Wako GELC-200 (manufactured by Wako Pure ChemicalIndustries Co., Ltd.) was used as a silica gel and n-hexane/ethylacetate=6:1 (volume ratio) was used as elution solvent. PGMB obtainedafter the purification was a colorless transparent liquid. The yield was2.80 g and percent yield was 25%.

SYNTHESIS EXAMPLE 6 Synthesis of Photopolymerization Initiator Component“trimethylolpropane tris(3-mercaptobutyrate) (TPMB)”

In a 100 mL volume egg-plant shaped flask, 2.68 g (20 mmol) oftrimethylolpropane, 7.57 g (63 mmol) of 3-mercaptobutanoic acid, 0.23 g(1.2 mmol) of p-toluenesulfonic acid monohydrate and 20 g of toluenewere charged and a Dean-Stark apparatus and a condenser tube wereattached to the flask. The content of the flask was heated at an oilbath temperature of 145° C. while stirring. After 3 hours from the startof the reaction, the reaction mixture was left to cool, followed byneutralizing the reaction mixture with 50 ml of an aqueous 5% sodiumhydrogen carbonate solution. Further, the reaction mixture was washedwith deionized water 2 times and dehydrated and dried over anhydrousmagnesium sulfate. Then, toluene was evaporated and the residue wassubjected to silica gel column chromatography to purify TPMB. WakoGELC-200 (manufactured by Wako Pure Chemical Industries Co., Ltd.) wasused as silica gel and n-hexane/ethyl acetate=5:1 (volume ratio) wasused as elution solvent. TPMB obtained after the purification was acolorless transparent liquid. The yield was 5.63 g and percent yield was64%.

SYNTHESIS EXAMPLE 7 Synthesis of Photopolymerization Initiator Component“trimethylolpropane tris(2-mercaptoisobutyrate) (TPMIB)”

In a 100 mL volume egg-plant shaped flask, 2.68 g (20 mmol) oftrimethylolpropane, 7.57 g (63 mmol) of 2-mercaptoisobutanoic acid, 0.23g (1.2 mmol) of p-toluenesulfonic acid monohydrate, and 20 g of toluenewere charged and a Dean-Stark apparatus and a cooling pipe were attachedto the: flask. The contents were heated on an oil bath at an oil bathtemperature of 145° C. while stirring. After 3 hours from the start ofthe reaction, the reaction mixture was left to cool, followed byneutralizing the reaction mixture with 50 ml of an aqueous 5% sodiumhydrogen carbonate solution. Further, the reaction mixture was washedwith deionized water 2 times and dehydrated and dried over anhydrousmagnesium sulfate. Then, toluene was evaporated and the residue wassubjected to silica gel column chromatography to purify TPMIB. Wako GELC-200 (manufactured by Wako Pure Chemical Industries Co., Ltd.) was usedas silica gel and n-hexane/ethyl acetate=5:1 (volume ratio) was used aselution solvent. TPMIB obtained after the purification was whitecrystal. The yield was 4.50 g and percent yield was 51%.

Dispersion-I: Preparation of a Carbon Black Dispersion

After mixing 438 mass parts (solid content 210 mass parts) of CyclomerACA-200 (hereinafter, abbreviated as ACA-200) manufactured by DaicelChemical Industries, Ltd., (solid content concentration 48%, weightaverage molecular weight in terms of polystyrene 19,000, solid contentacid value 116 mg/g), which is an acrylic copolymer having an acryloylgroup and a carboxyl group in a side chain, 210 mass parts (solidcontent 84 mass parts) of DP-1, the copolymer dispersant obtained inSynthesis Example 3, 546 mass parts of Special Black 250 (manufacturedby Degussa) as carbon black, and 3,000 mass parts of cyclohexanone, theresultant was premixed using a disperser. Further, this mixed solutionwas dispersed in a continuous annular type bead mill (trade name:SpikeMill Model SHG-4, manufactured by Inoue Seisakusho Co., Ltd.). The beadsused were zirconia beads having a diameter of 0.65 mm and the fillingratio of the beads in the vessel was set to 80 volume %. The peripheralspeed of the rotor was 12 m/second, the discharge rate of the carbonblack dispersion was 1 liter/minute, and the temperature was set toabout 30° C. The retention time of the carbon black dispersion in thevessel was set to 6 minute (for operation time of 1 hour). Dispersion-1was thus obtained.

In a manner similar to the above, Carbon Black Dispersions-2 to -6having the compositions shown in Table 1 were obtained. TABLE 1 BlendingComposition of Carbon Black Dispersion(Mass Part) Acrylic CopolymerDispersant Carbon Black Organic Solvent Total Dispersion-1 ACA-200 DP-1Special Black 250 Cyclohexanone 4194 (840) 438 210 (84) 546 (546) 3000(210) Dispersion-2 ACA-200 DP-1 Raven 1040 Cyclohexanone 4194 (840) 438210 (84) 546 (546) 3000 (210) Dispersion-3 ACA-200 DP-1 Raven 1080Cyclohexanone 4194 (840) 438 210 (84) 546 (546) 3000 (210) Dispersion-4AP-1 DP-1 Raven 1060 Cyclohexanone 4195 (840) 689 210 (84) 546 (546)2750 (210) Dispersion-5 AP-1 DP-1 Raven 1080 Cyclohexanone 4195 (840)689 210 (84) 546 (546) 2750 (210) Dispersion-6 AP-2 DP-1 Raven 1080Cyclohexanone 4193 (840) 712 210 (84) 546 (546) 2725 (210)*In the parentheses( ) Solid content composition is shown.Special Black 250 (manufactured by Degussa): Primary particle diameter56 nm, Specific surface area 40BET-m²/g, DBP oil absorption 40 ml/100 gRaven 1040 (manufactured by Columbian Carbon Co): Primary particlediameter 28 nm Specific surface area 92BET-m²/g, DBP oil absorption 100ml/100 gRaven 1060 (manufactured by Columbian Carbon Co): Primary particlediameter 30 nm, Specific surface area 66BET-m²/g, DBP oil absorption 50ml/100 gRaven 1080 (manufactured by Columbian Carbon Co): Primary particlediameter 28 nm, Specific surface area 84BET-m²/g, DBP oil absorption 60ml/100 gEvaluation of Black Matrix Resist:

The following reagents were used.

Compound Having an Ethylenically Unsaturated Group (Monomer) (B)

Dipentaerythritol hexaacrylate (hereinafter, abbreviated as DPHA:manufactured by Toa Gosei Co., Ltd.),

Photopolymerization Initiator (C)

-   (1) 4,4′-Bis(N,N-diethylamino)benzophenone (hereinafter, abbreviated    as EMK: manufactured by Hodogaya Chemicals Co. Ltd.-   (2) 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one    (trade name: Irgacure 907: manufactured by Chiba Specialty Chemicals    K.K.)-   (3) 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone-1    (trade name: Irgacure 369: manufactured by Chiba Specialty Chemicals    K.K.)    Thiol Compound (D)-   (1) Trimethylolpropane tris(3-mercaptopropionate) (hereinafter,    abbreviated as TPMP: manufactured by Yodo Kagaku Co., Ltd.)-   (2) 2-Mercaptobenzothiazole (hereinafter, abbreviated as MBT:    manufactured by Tokyo Kasei Kogyo Co., Ltd.    Organic Solvent (E)

Cyclohexanone (manufactured by Wako Pure Chemical Industries Co., Ltd.).

EXAMPLE 1 Preparation of black Matrix Resist

Dispersion I (420 mass parts, containing 21.0 mass parts of acryliccopolymer as solid content, 8.4 mass parts of dispersant, and 54.6 massparts of carbon black), DPHA (8.4 mass parts) as a monomer, EMK (1.0mass part) as a photopolymerization initiator, MHABI (5.0 mass parts),TPMB (5.0 mass parts) as a multifunctional thiol compound, cyclohexanone(150 mass parts) were mixed and stirred for 2 hours, and then filteredthrough a filter having a pore diameter of 0.8 μm (filter for GFPmanufactured by Kiriyama Glass Works Co.) to prepare a black matrixresist of Example 1.

EXAMPLE 2 to 6 and COMPARATIVE EXAMPLES 1 and 2

Black matrix resist compositions of Examples 2 to 6 and ComparativeExamples 1 and 2 were prepared using the compositions shown in Table 2and by the same method as that in Example 1.

Measurement of Photosensitivity:

The black matrix resist compositions of Examples 1 to 6 and ComparativeExamples 1 and 2 were spin-coated onto glass substrates (size: 100×100×1mm) to a dry thickness of about 1 μm and left to stand at roomtemperature for 30 minutes. Thereafter, the solvent was dried at 70° C.for 20 minutes. After the thickness of each resist was preliminarilymeasured using a film thickness gauge (manufactured by Tokyo SeimitsuCo., Ltd., SURFCOM 130A), the resist was photocured through a quartzmade photomask in a photolithography machine having incorporated thereina super high pressure mercury lamp (manufactured by Ushio Inc., tradename: Multilight ML-251A/B) by automatically varying the exposure amountstepwise. The exposure amount was measured using an ultraviolet integralactinometer (manufactured by Ushio Inc., trade name: UIT-150, lightreceiving part UVD-S365). The quarts made photomask used had formedtherein with line/space patterns of 5, 7, 10, 30, 50, 70, or 100 μm.

The exposed resist was alkali-developed with an aqueous solution (25°C.) containing 0.25% of Developer 9033 (manufactured by Shipley Far EastLtd.) which contains potassium carbonate and 0.03% of sodiumdodecylbenzenesulfonate for a predetermined time (the developing timewas set to double the time (tD) required for the film before exposure tobe completely dissolved by alkali development; in the present Example,tD was 15 seconds). After the alkali development, the glass substrateswere washed and then dried by air spray. The thickness of the resistfilms that remained was measured and the ratio of the remaining film wascalculated. The remaining film ratio was calculated according to thefollowing formula. photocuring operations were performed in the samemanner by varying the exposure amount and the relationship between theexposure amount and remaining film ratio was plotted in a graph, and theexposure amount at which the remaining film ratio reached saturation wasobtained.Remaining film ratio (%)={(film thickness after alkalidevelopment)/(film thickness before alkali development)}×100

Next, the line width of the resist formed at a portion where theline/space of the photomask was 10 μm was measured under an opticalmicroscope (manufactured by Keyence Corporation, VH-Z250). The minimumexposure amount at which the remaining film ratio after alkalidevelopment reached saturation and the same line width as that of thephotomask was obtained by the above-mentioned method was defined as thephotosensitivity of the black matrix resist. The results obtained areshown in Table 2.

Measurement of Resolution:

In the evaluation of photosensitivity described above, each black matrixresist was photocured with an exposure amount that correspondeds to itsphotosensitivity, alkali developed in the same manner as described aboveand observed under an optical microscope. The minimum line width thatremained and was equivalent to the line width of the photomask wasdefined as resolution of the black matrix resist. The results obtainedare shown in Table 2.

OD Value (Optical Density):

The black matrix resist compositions of Examples 1 to 6 and ComparativeExamples 1 and 2 were spin-coated onto glass substrates (size:100×100mm), and dried at room temperature for 30 minutes, followed bydrying the solvent at 70° C. for 20 minutes. After photocuring atexposure amounts corresponding to photosensitivity of the respectiveresists, the resists were post-baked at 200° C. for 30 minutes, and theresulted resist-coated glass substrates were used to measure OD values.The OD values were determined using a calibration curve prepared bymeasuring a transmittance at 550 nm using a standard plate whose ODvalue is already known. The results obtained are shown in Table 2.

Storage Stability:

The photosensitivities of the resist compositions of Examples 1 to 6 andComparative Examples 1 and 2 immediately after they were prepared weremeasured by the above-mentioned method. In addition, after thepreparation, the samples were stored at room temperature for 4 weeks inthe dark and the photosensitivities of each example and comparativeexample were measured. The results are shown in Table 2.

From Table 2, it is apparent that use of thiol compounds having two ormore mercapto-group-containing groups in which carbon atoms at theα-position and/or β-position with respect to the mercapto group have asubstituent results in obtaining balanced photosensitivity and storagestability, and in addition satisfactory characteristics as a blackmatrix resist.

That is, in the case of monofunctional thiols, the photosensitivity islow and storage stability is poor (Comparative Example 2), and also,although higher sensitivity can be achieved by using a conventionallinear type thiol (laurylmercaptan, octanethiol, HSCH₂CH₂COOHderivatives, etc.), the storage stability is not sufficiently improved(Comparative Example 1). It is only by use of the thiol compound of thepresent invention that has a so-called branched structure at theα-position and/or β-position in combination with existingphotopolymerization initiator in photosensitive composition (Examples 1to 6) high sensitivity can be maintained and storage stability can beimproved.

In the case of photocuring by radical polymerization, complete curing isdifficult to occur at the interface with air due to oxygen in the airinhibiting the polymerization. Accordingly, it is a usual practice toprovide an air-shielding layer such as a cover film so as to prevent thesurface from contacting air, or to perform photocuring under atmosphereof an inert gas such as argon gas or nitrogen. In contrast, thephotosensitive composition of the present invention exhibits sufficientcuring properties regardless of whether oxygen exists or not and can beused as a photosensitive composition for color filters for which it ispreferable to use no oxygen shielding film. TABLE 2 Results ofEvaluation of Black Matrix Resist Item of Evaluation Storage stabilityComposition of black matrix resist (mass part) (PhotosensitivityCompound (mJ/cm²) having an After ethylenically Organic Photo- Reso- ODImmediately 4 weeks Carbon black unsaturated Photopolymerization Thiolsolvent sensitivity lution Value after at room dispersion group intiatorcompound (cyclohexanone) (mJ/cm²) (μm) (/μm) preparation temperatureExam- 1 Dispersion 1 DPHA EMK MHABI TPMB 150.0 40 6 4.2 40 60 ple 420.08.4 1.0 5.0 5.0 2 Dispersion 2 DPHA EMK MHABI TPMB 150.0 100 6 4.0 100120 420.0 8.4 1.0 5.0 5.0 3 Dispersion 3 DPHA EMK MHABI TPMB 150.0 80 64.2 80 100 420.0 8.4 1.0 5.0 5.0 4 Dispersion 4 DPHA EMK Irgacure TPMB150.0 80 6 4.2 80 100 420.0 8.4 1.0 907 5.0 5.0 5 Dispersion 5 DPHAIrgacure PGMB 150.0 80 6 4.2 100 120 420.0 8.4 369 5.0 6.0 6 Dispersion6 DPHA EMK MHABI TPMIB 150.0 80 6 4.0 80 80 420.0 8.4 1.0 5.0 10.0  Com*1 Dispersion 1 DPHA EMK MHABI TPMP 150.0 20 6 4.2 20 300 420.0 8.4 1.05.0 5.0 2 Dispersion 1 DPHA EMK MHABI MBT 150.0 300 20 4.2 300 500 420.08.4 1.0 5.0 5.0 or more*Com indicates Comparative Example

INDUSTRIAL APPLICABILITY

By using a branched multifunctional thiol compound having a so-calledbranched structure at the α-position and/or β-position in combinationwith a conventional photopolymerization initiator, it is possible tosimultaneously achieve maintenance and improvement of high sensitivityand improvement of storage stability, which has not been achieved by useof conventional liner type thiol or conventional aromatic thiols such asmercaptobenzothiazole. The photosensitive composition of the presentinvention containing such a branched multifunctional thiol compound issuitable for the production of black matrix resist compositions havinghigh precision and high light shielding ratio and is suitableparticularly for development type resists that form patterns with highresolution.

1. A photosensitive composition for color filter black matrix resists,comprising (A) a binder resin having a carboxyl group, (B) a compoundhaving an ethylenically unsaturated bond, (C) a photopolymerizinginitiator, (D) a thiol compound having two or moremercapto-group-containing groups in which carbon atom(s) at α-positionand/or β-position with respect to the mercapto group have a substituent,and (E) an organic solvent.
 2. The photosensitive composition for colorfilter black matrix resists according to claim 1, wherein at least oneof the substituents in the thiol compound (D) is an alkyl group.
 3. Thephotosensitive composition for color filter black matrix resistsaccording to claim 2, wherein the alkyl group of the thiol compound (D)is a linear or branched alkyl group having 1 to 10 carbon atoms.
 4. Thephotosensitive composition for color filter black matrix resistsaccording to claim 1, wherein the mercapto-group-containing group of thethiol compound (D) is represented by the following formula (1)—(CH₂)_(m)C(R¹)(R²)(CH₂)_(n)SH   (1) (in the formula, R¹ and R²independently represent each a hydrogen atom or an alkyl group, at leastone of R¹ and R² is an alkyl group, m is an integer of 0 or 1 to 2, andn is 0 or 1.)
 5. The photosensitive composition for color filter blackmatrix resists according to any one of claims 1 to 4, wherein the thiolcompound (D) is an ester of a mercapto group-containing carboxylic acidrepresented the following formula (2)HO—CO—(CH₂)_(m)C(R¹)(R²)(CH₂)_(n)SH   (2) (in the formula, R¹ and R²independently represent each a hydrogen atom or an alkyl group, at leastone of R¹ and R² is alkyl group, m is an integer of 0 or 1 to 2, and nis 0 or 1) with a multifunctional alcohol.
 6. The photosensitivecomposition for color filter black matrix resists according to claim 5,wherein the multifunctional alcohol is one or more of compounds selectedfrom a group consisting of alkylene glycol (provided that the alkylenegroup has 2 to 10 carbon atoms and may be branched), diethylene glycol,glycerol, dipropylene glycol, trimethylolpropane, pentaerythritol anddipentaerythritol.
 7. The photosensitive composition for color filterblack matrix resists according to claim 5, wherein the multifunctionalalcohol is a high molecular polymer having a hydroxyl group.
 8. Thephotosensitive composition for color filter black matrix resistsaccording to claim 1, wherein the binder resin having a carboxyl group(A) further has an ethylenically unsaturated group.
 9. Thephotosensitive composition for color filter black matrix resistsaccording to claim 8, wherein the binder resin having a carboxyl group(A) is an acrylic copolymer.
 10. The photosensitive composition forcolor filter black matrix resists according to claim 1, wherein thephotopolymerization initiator (C) contains a hexaaryl biimidazolecompound and/or an aminonacetophenone compound.
 11. The photosensitivecomposition for color filter black matrix resists according to claim 10,wherein the hexaaryl biimidazole compound is represented by thefollowing formula (3)

(in the formula, R³ represents a halogen atom, R⁴ represents an alkylgroup having 1 to 4 carbon atoms that may have a substituent, or analkoxy group that may have a substituent).
 12. The photosensitivecomposition for color filter black matrix resists according to claim 1,wherein the photopolymerization initiator (C) contains at least onecompound selected from the group consisting of a benzophenone-basedcompound, a thioxanthone-based compound, and a ketocoumarin-basedcompound as a sensitizer.
 13. The photosensitive composition for colorfilter black matrix resists according to claim 1, wherein respectivecomponents excluding the organic solvent (E) are contained in thefollowing ratio based on the total amount of the components: (A) abinder resin having a carboxyl group 30 to 70 mass % (B) a compoundhaving an ethylenically unsaturated  5 to 40 mass % compound (C) aphotopolymerization initiator  3 to 30 mass % (D) a thiol compoundhaving two or more mercapto-  3 to 30 mass %. group-containing groups inwhich carbon atoms at α-position and/or β-position with respect to themercapto group have a substituent


14. A color filter black matrix resist composition comprising thephotosensitive composition for color filter black matrix resistsaccording to claim 1 and a black pigment (F).
 15. The color filter blackmatrix resist according to claim 14, wherein the black pigment (F)contains carbon black.
 16. The color filter black matrix resistcomposition according to claim 14, wherein respective componentsexcluding the organic solvent (E) are contained in the following ratiosbased on the total amount of the components: (A) a binder resin having acarboxyl group 10 to 30 mass % (B) a compound having an ethylenicallyunsaturated  2 to 20 mass % compound (C) a photopolymerization initiator 2 to 15 mass % (D) a thiol compound having two or more mercapto-  2 to15 mass % group-containing groups in which carbon atoms at α-positionand/or β-position with respect to the mercapto group have a substituent(F) a black pigment 40 to 70 mass %.